Ejector and refrigerating machine

ABSTRACT

An ejector that does not inhibit a flow of fluid and a refrigerating system provided with the ejector. The ejector includes a hollow passage, i.e. a negative pressure generating passage, through which fluid flows, a member having a hole disposed in the hollow passage, a negative pressure chamber disposed downstream of the member having a hole, and a hollow passage, i.e. an inlet passage, open to the negative pressure chamber. A filter, such as a mesh, is disposed in the inlet passage.

TECHNICAL FIELD

The present invention relates to an ejector which draws in fluid bygenerating a negative pressure, and a refrigerating system provided withsuch an ejector.

BACKGROUND ART

FIG. 3 is a schematic diagram showing the configuration of arefrigerating system provided with a conventional ejector. In thisrefrigerating system, the condenser 1 is connected to the evaporator 2by refrigerant pipes 3 and 7, and the refrigerant pipe 7 is alsoconnected to the compressor 5. The refrigerant in the refrigerant pipes3 and 7 is circulated between the condenser 1 and the evaporator 2 bythe compressor 5.

In such a conventional refrigerating system, a problem may arise when apiece of the wire mesh, which is disposed in the mist tank 8, breaks offand flows out toward the ejector 10 together with lubricating oil. Thepiece of wire mesh may become stuck in the ejector 10 and inhibit thecirculating flow of the lubricating oil.

The present invention takes into consideration the above-mentionedcircumstances, and has as an object to provide a refrigerating systemand an ejector which does not interfere with the flow of fluid.

DISCLOSURE OF INVENTION

In accordance with one aspect of the invention, an ejector includes anegative pressure generating passage through which fluid flows; a memberhaving a small hole disposed in the negative pressure generatingpassage, the fluid flowing through the small hole of the member; anegative pressure chamber disposed downstream of the member having asmall hole; and an inlet passage opening to the negative pressurechamber, wherein a filter means is disposed in the inlet passage.

According to the above ejector, solid contaminants, such as pieces ofwire mesh, contained in the fluid which flows into the negative pressurechamber via the inlet passage, may be removed by the filter means.

In accordance with another aspect of the invention, the filter means isa mesh type member.

According to the above ejector, solid contaminants may be removed whenthe fluid passes through the mesh type member.

In accordance with another aspect, the present invention provides arefrigerating system including a lubricating oil tank; an evaporator; anequalizing pipe member which connects the lubricating oil tank to theevaporator; a mist tank connected to the equalizing pipe member, themist tank separating lubricating oil from a fluid which flows throughthe equalizing pipe member; and an ejector for removing the lubricatingoil, which is separated in the mist tank, from the mist tank. Theejector includes a negative pressure generating passage through which afluid flows; a member having a small hole disposed in the negativepressure generating passage, the fluid flowing through the small hole ofthe member; a negative pressure chamber disposed at a downstream side ofthe member having a small hole; and an inlet passage opens to thenegative pressure chamber, the inlet passage being communicated with themist tank. The ejector is the same as the one mentioned above.

In the above refrigerating system, the lubricating oil separated in themist tank flows into the ejector. Although a lubricating oil separationmeans, such as a wire mesh, is provided in the mist tank in order toseparate the lubricating oil, solid impurities, such as wire meshpieces, may sometimes be included in the lubricating oil from the misttank. Such solid impurities are removed by a filter means disposed inthe ejector.

In yet another aspect of the invention, in the above refrigeratingsystem, the fluid which flows through the negative pressure generatingchamber comprises lubricating oil discharged from an outlet of an oilpump.

The oil pump may be disposed in the oil tank or outside the oil tank aslong as it is disposed within the passages for supplying the lubricatingoil in the oil tank to the portions of the compressor which require oilsupply.

In yet another aspect of the invention, the refrigerating system furtherincludes a non-return valve provided within the passage connecting theejector to the negative pressure chamber, the non-return valve beingcapable of preventing flow from the negative pressure chamber toward thefilter means.

According to the above refrigerating system, it becomes possible toblock the flow from the negative pressure chamber side of the ejectortoward the filter means, and it becomes possible to prevent the piecesof the wire mesh caught by the filter means from flowing backward.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing an ejector according to an embodiment of thepresent invention which may be used in a refrigerating system.

FIG. 2 is a schematic diagram showing the configuration of arefrigerating system according to an embodiment of the present inventionusing the ejector shown in FIG. 1.

FIG. 3 is a schematic diagram showing the configuration of aconventional refrigerating system.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be explained withreference to the accompanying drawings. Note that the same numerals areused for elements which are the same as the ones shown in FIG. 3, andthe explanation thereof will be omitted.

The compressor 5 is provided with the oil tank 6 (i.e., a lubricatingoil tank) which contains lubricating oil, and the oil tank 6 isconnected to the evaporator 2 via an equalizing pipe 4 in order to makethe pressure of the oil tank 6 the lowest in the refrigerating cycle.Although the refrigerant vapor and the lubricating oil as oil mist fromthe oil tank 6 flow through the equalizing pipe 4 since the pressure inthe oil tank 6 is high, the equalizing pipe 4 is provided with the misttank 8 in order to prevent the oil mist from flowing into the evaporator2. A wire mesh (not shown in the figure) is disposed in the mist tank 8so that oil mist, which is contained in a refrigerant vapor-oil mistmixture supplied from the oil tank 6 via the equalizing pipe 4, may beattached to the wire mesh and drip therefrom when the refrigerantvapor-oil mist mixture passes through the wire mesh.

The mist tank 8 is connected to an ejector 20 via a pipe 9 so thatlubricating oil, which has been separated from the refrigerant vapor-oilmist mixture in the mist tank 8, can be discharged via the pipe 9. Also,the ejector 20 is connected to the main lubricant route of therefrigerating system via a pipe 11, and to the oil tank 6 via a pipe 12.

FIG. 1 is a diagram showing the ejector 20 according to an embodiment ofthe present invention. The ejector 20 may be used in the refrigeratingsystem instead of the conventional ejector 10 shown in FIG. 3.

The ejector 20 according to an embodiment of the present invention issubstantially T-shaped, and the pipe 11, which is connected to thelubricant route, and the pipe 12, which is connected to the oil tank 6,are connected to the ejector 20 so as to be aligned in a straight line.Also, the pipe 9, which connects the ejector 20 to the mist tank 8, isdisposed so as to be perpendicular to the pipes 11 and 12.

A hollow passage (a negative pressure generating passage) 25, which isdesigned to be a straight line, and another hollow passage (an inletpassage) 26, which is designed so as to be substantially perpendicularto the hollow passage 25, are formed in the ejector 20. A hollow orificemember 28 having a small hole 27 at an end portion thereof, is engagedwith a nozzle member 30 having a hollow portion 29, both ends of whichare tapered so as to increase in size towards the ends thereof as shownin FIG. 1, and they are inserted and attached to the inner wall of thehollow passage 25. A negative pressure chamber 31, which is open to thehollow passage 26, is formed between the orifice member 28 and thenozzle member 30.

Also, a disc-shaped mesh (a filtering member, a net device) 35 isdetachably disposed in the hollow passage 26.

The pipe 11 is connected to the outside of the orifice member 28 (i.e.,the hollow passage 25) via a nut 11 a, and the pipe 12 is connected tothe outside of the nozzle member 30 via a nut 12 a. Also, the pipe 9 isconnected to the hollow passage 26 via a nut 9 a.

The pipe 11 is arranged as shown in FIG. 2.

That is, the refrigerating system according to an embodiment of thepresent invention may be a turbo refrigerating system, and the mainroute of the lubricating oil is normally constructed so that thelubricating oil is supplied to the portions of the compressor 5, whichrequire oil supply, from the oil tank 6 via the pipe 11 by means of anoil pump 13 disposed in the oil tank 6. The lubricating oil which hasbeen used for lubricating the compressor 5 is returned to the oil tank 6via the pipe 11. An oil cooler may be disposed along the route of thelubricating oil.

On the other hand, a part of the pipe 11 is branched from theabove-mentioned main route of the lubricating oil and connected to theejector 20 so that a portion of the lubricating oil is supplied to theejector 20. The lubricating oil which is supplied to the ejector 20 isreturned to the oil tank 6 via the pipe 12.

Accordingly, the fluid which flows through the negative pressuregenerating passage 25 of the ejector 20 is the lubricating oil suppliedfrom the oil tank 6 by means of the oil pump 13.

Note that although the oil pump 13 is disposed in the oil tank 6 in thisembodiment of the invention as shown in FIG. 2, the oil pump 13 may ofcourse be disposed outside of the oil tank 6. That is, the oil pump 13may be disposed anywhere as long as it is disposed along the passage forsupplying the lubricating oil in the oil tank 6 to the portions of thecompressor 5 which require oil supply.

In the refrigerating system having the above-mentioned configuration,the refrigerant in the refrigerant pipes 3 and 7 is circulated betweenthe condenser 1 and the evaporator 2 by the actuation of the compressor5. Accordingly, the refrigerant vapor-oil mist mixture from the oil tank6 flows through the equalizing pipe 4, and the oil mist is separatedfrom the mixture in the mist tank 8.

Also, as mentioned above, the lubricating oil flows into the ejector 20via the pipe 11. The lubricating oil is injected to the nozzle member 30via the small hole 27 of the orifice member 28. At that time, a negativepressure is generated in the negative pressure chamber 31, which islocated between the orifice member 28 and the nozzle member 30, and thelubricating oil, which has been separated in the mist tank 8, is drawninto the ejector 20 and flows into the nozzle member 30 due to thenegative pressure thus generated. The lubricating oil, which flows intothe nozzle member 30, is returned to the oil tank 6 via the pipe 12.

As mentioned above, since a wire mesh is disposed in the mist tank 8,pieces of the wire mesh may break off and the broken off pieces thereofmay flow into the ejector 20 together with the lubricating oil. However,because the filter means 35 is disposed in the hollow passage 26 of theejector 20, the broken off pieces of the wire mesh are caught by thefilter means 35 and do not reach the nozzle member 30. The pieces of thewire mesh caught by the filter means 35 in the manner mentioned abovemay be removed by periodically taking out and cleaning the mesh 35.

Also, according to another embodiment of the invention, a non-returnvalve 14 may be provided along the pipe 9 as shown in FIG. 2 to preventflow from the ejector 20 to the mist tank 8.

In this manner, it becomes possible to prevent flow from the negativepressure chamber 31 toward the filter means 35, and therefore, toprevent the pieces of the wire mesh caught by the filter means 35 fromflowing backward.

As explained above, since the mesh 35 is provided for the ejector 30 inthe refrigerating system according to an embodiment of the presentinvention, it becomes possible to prevent the nozzle member 30 frombeing clogged by ruptured wire mesh pieces. Also, since the non-returnvalve 14 is provided along the pipe 9, it becomes possible to preventthe pieces of the wire mesh caught by the filter means 35 from flowingbackward. Accordingly, it becomes possible to prevent the circulation oflubricating oil from being inhibited.

Also, since no pressure loss occurs as in the case where a strainer isused, the performance of the ejector 20 is excellent as compared withthe case where a separate strainer is provided for the ejector 10 in aconventional refrigerating system (refer to FIG. 3)

Industrial Applicability

As explained above, according to the present invention, since a filtermeans is provided in the ejector, and a non-return valve is providedalong the pipe, it becomes possible to prevent clogging of the ejectorby wire mesh pieces, and it becomes possible to prevent the pieces ofthe wire mesh caught by the filter means from flowing backward.Accordingly, it becomes possible to prevent the circulation oflubricating oil from being inhibited.

What is claimed is:
 1. A refrigerating system, comprising: a lubricatingoil tank; an evaporator; an equalizing pipe member connecting saidlubricating oil tank to said evaporator; a mist tank connected to saidequalizing pipe member and which separates lubricating oil from a fluidwhich flows through said equalizing pipe member; and an ejector whichremoves the lubricating oil separated in said mist tank from said misttank, the ejector including: a negative pressure generating passagethrough which a fluid flows; a member having a first hole disposed insaid negative pressure generating passage, said fluid flowing throughsaid first hole of said member; a negative pressure chamber disposed ata downstream side of said member having a second hole; an inlet passageopen to said negative pressure chamber, said inlet passage communicatingwith said mist tank; and a filter deposed in said inlet passage.
 2. Arefrigerating system as set forth in claim 1, wherein said filtercomprises a mesh member.
 3. A refrigerating system as set forth in claim1, wherein said fluid which flows through said negative pressuregenerating chamber comprises lubricating oil discharged from an outletof an oil pump.
 4. A refrigerating system as set forth in claim 2,wherein said fluid which flows through said negative pressure generatingchamber comprises lubricating oil discharged from an outlet of an oilpump.
 5. A refrigerating system as set forth in claim 3, furthercomprising: a non-return valve provided along a passage connecting saidejector to said negative pressure chamber, said non-return valveconfigured to prevent a flow from said negative pressure chamber towardsaid filter.
 6. A refrigerating system as set forth in claim 4, furthercomprising: a non-return valve provided along a passage connecting saidejector to said negative pressure chamber, said non-return valveconfigured to prevent a flow from said negative pressure chamber towardsaid filter.
 7. An ejector, comprising: a negative pressure generatingpassage through which fluid flows; a member having a first hole disposedin said negative pressure generating passage, said fluid flowing throughsaid first hole of said member; a negative pressure chamber disposeddownstream of said member having a second hole; and an inlet passageopen to said negative pressure chamber; and a filter disposed in saidinlet passage.
 8. An ejector as set forth in claim 7, wherein saidfilter comprises a mesh member.